Air pollution and human brain pathology: A role for air pollutants in the pathogenesis of alzheimer’s disease

Adverse health effects associated with chronic exposures to air pollutants (indoor, outdoor, and occupational settings) are an important issue for millions of people around the world. As the world population becomes older, significant increases in neurodegenerative diseases such as Alzheimer’s have been projected over the next decades (Brookmeyer, Gray, and Kawas 1998; Hebert et al. 2003). Alzheimer’s disease (AD) is an irreversible, fatal brain disorder that presently affects 4.5 million people in the United States and it is projected that it will affect between 13 and 16 million by 2050 (Brookmeyer, Gray, and Kawas 1998; Hebert et al. 2003). Alzheimer’s patients have a major medical, social, and economic impact, thus any factors that could modify these projections need to be pursued and integrated into multidisciplinary studies of AD. The role played by the environment in the pathogenesis of AD is unclear (Brown, Lockwood, and Sonawane 2005). Our findings suggest that exposures to significant levels of particulate matter and photo-oxidants may accelerate the appearance of precursors of Alzheimer’s disease in sentinel animals and in humans.